在JBPM中我们经常需要动态的决定业务流程的走向,JBPM本身提供了Decision这个标签让我们可以通过expression来动态的决定流程应该如何路由.下面给出了一个非常简单的使用Decision的例子
xml定义流程图
xml定义文件:
xml version="1.0" encoding="UTF-8" ?>

< process-definition  xmlns ="urn:jbpm.org:jpdl-3.2"  name ="decisiontest" >
     < start-state  name ="start" >
         < transition  name =""  to ="task1" > transition >
     start-state >
     < end-state  name ="end1" > end-state >
     < task-node  name ="task1" >
     < task > task >
         < transition  name =""  to ="decision1" > transition >
     task-node >
     < decision  name ="decision1"  expression ="#{role=='tr1'?'tr1':'tr2'}" >
         < transition  name ="tr1"  to ="task2" > transition >
         < transition  name ="tr2"  to ="task3" > transition >
     decision >
     < task-node  name ="task2" >
         < task > task >
         < transition  name =""  to ="end1" > transition >
     task-node >
     < task-node  name ="task3" >
         < task > task >
         < transition  name =""  to ="end1" > transition >
     task-node >
process-definition >
 
java测试代码:
package  com.decision;

 import  org.jbpm.graph.def.ProcessDefinition;
 import  org.jbpm.graph.exe.ProcessInstance;

 import  junit.framework.TestCase;

 public   class  DecisionTest  extends  TestCase  {
    ProcessDefinition procdef;
    ProcessInstance procInstance;
    
    @Override
    protected void setUp() throws Exception {
        // TODO Auto-generated method stub
        super.setUp();
       procdef=ProcessDefinition.parseXmlResource("decision/decisiontest/processdefinition.xml");
       procInstance=new ProcessInstance(procdef);
    }

    @Override
    protected void tearDown() throws Exception {
        // TODO Auto-generated method stub
        super.tearDown();
    }

    public void testProcess(){
        assertEquals("start", procInstance.getRootToken().getNode().getName());
        procInstance.signal();
        assertEquals("task1",procInstance.getRootToken().getNode().getName());
        procInstance.getContextInstance().setVariable("role", "tr2");
        procInstance.signal();
        assertEquals("task2",procInstance.getRootToken().getNode().getName());
        assertEquals("tr1", (String)procInstance.getContextInstance().getVariable("role"));
        procInstance.signal();
        assertTrue(procInstance.hasEnded());
    }
}
来自网络转载，不过测试了下，用的junit测试，发现运行通不过去，老报空指针异常，有知道原因的请告诉我